Attempts will be made to isolate the isoenzymes of the catalytic subunit of the cyclic AMP-dependent protein kinase from gastric mucosa. If these enzymes are obtained in sufficient quantity, aminoacid compostition will be determined. The role of Mg ions in regulating the activity of this enzyme will be investigated. The cyclic nucleotide phosphodiesterases of the rabbit gastric mucosa will be characterized with respect to molecular weight, kinetics, and effects of potential effector molecules. Attempts will be made to isolate from the bullfrog gastric mucosa oxyntic cells that are responsive to secretagogues. BIBLIOGRAPHIC REFERENCES: Reimann, E.M. and Schlender, K.K. (1976) J. Cyclic Nucl. Res. 2, 39-46. "Multiple forms of glycogen synthase kinase: isolation of forms which are independent of cyclic AMP." Schlender, K.K. and Reimann, E.M. (1976) Fed. Proc. Abstract in press. "Glycogen synthase kinases: occurrence of forms which are independent of cyclic AMP."